James Ward has been chosen ahead of British number two Dan Evans as Great Britain's second singles player for the Davis Cup quarter-final in Italy.
Captain Leon Smith has opted to use Ward, the British number three, along with Andy Murray for Friday's singles rubbers in Naples.
Murray was unwell on Wednesday but was able to train on Thursday evening.
Colin Fleming and Ross Hutchins complete the line-up, although Murray could feature in Saturday's doubles.
Murray developed a stomach bug on Wednesday and stayed away from the draw ceremony on Thursday morning.
But after spending the day resting at the team hotel, he was fit enough to complete a 50-minute early-evening training session, and the British team are confident he will be able to play on the opening day.
"I think we've all had a bit of a dodgy stomach over the last couple of days, I don't know what it is with the food," joked Ward. "I think Andy will be fine to play."
Ward will open against world number 13 Fabio Fognini on Friday, before Murray takes on Andreas Seppi, ranked 34th.
The tie - Britain's first quarter-final since 1986 - is taking place on clay, the surface on which Ward beat Sam Querrey, then ranked 45th in the world, in Britain's first-round win over the United States.
Evans was left out of that tie, having featured in the previous four, but he was recalled for the trip to Naples and felt he had every chance of making the final selection.
"I wouldn't say James is the man in possession," Evans told the Birmingham Mail newspaper on Tuesday. "I have got a very good chance of playing."
But Smith told BBC Sport: "Both players, importantly, have played a big part in the team over the last few years to get us to this point.
"The surface has played a significant part in coming to this decision. James has spent more time on clay and has more experience on it. Working with him to implement some of the things that we'd like to do tactically, it felt for me James had the slight edge."
Asked whether the competition for places had caused any bad feeling in the team, Ward said: "No, me and Evo get on really well and we've been laughing about it all week - we always thought someone might get the chop.
"But we spoke after the decision and he's going to stick around and support, which is good from him."
Murray remains a strong option to team up with Fleming in the doubles on Saturday if he comes through the opening day unscathed.
If not, Hutchins - returning to Davis Cup duty for the first time since 2012 after recovering from from Hodgkin's lymphoma last year - will step in to play alongside Fleming, his regular doubles partner.
The weather forecast suggests play could be interrupted on the three days, with provisions in place for an extension until Monday if necessary.